I have searched 100 of forums and can't find any information to the Reinstallation and Uninstallation of the Adaptive Agent on Zenworks 11.2 CM & PM.

Here the Problem:
We were using ZCM 6.4 with the Adaptive Agent 6.4 in our enviroment. Now I have set up a new Server (different IP) with ZCM and ZPM 11.2 and want to move all my Clients from the 6.4 enviroment (Win7 and XP) to the new Server. I know I have to install the new 11.2 Agent on all the old Clients, that is no Problem with the ZCM deployment. I also know that it is possible to leave the 6.4 running while working with the 11.2 Agent, but this is not wanted in our Enviroment.
My question is, how do I uninstall the old 6.4 Agent on all the Clients? With over 100 Clients spread all over the World its not very easy to do... Is it possible to uninstall the old agent with a Batch-skript or an hidden feature of the ZCM 11.2?

My second question is, I've set up a Test enviroment with an Server2008R2 (ZCM+ZPM 11.2) and a few Clients (WinXP+Win7). Today I reinstalled the ZCM Server (IP, Zone-Name and Hostname stayed the same) and now the Clients can't find the ZCM-Server any more. Is it possible to change the Agent configuration over the ZCM? When I try to deploy the Agent again on the Client, I get the Error that the Agent is allready installed. Do I really have to uninstall the Agent by hand and then deploy the agent again over the ZCM?

With best regards,